During the UN-Habitat III conference in October 2016, the European Union, the OECD and the World Bank launched a voluntary commitment to develop a global, people-based definition of cities and settlements. This commitment will support the implementation of the new urban agenda. It will also support the monitoring and the comparison of the urban Sustainable Develompent Goal (SDG). Several of the indicators linked to this goal are highly sensitive to where the boundary is drawn around a city.
The goal of the commitment is to present a definition to the UN Statistical Commission in 2019. Two linked definitions are being tested: The degree of urbanisation and the EU-OECD functional urban area definition.
In 2017, the Food and Agricultural Organization (FAO) has joined this commitment linking it with the Global Strategy to improve Agricultural and Rural Statistics.
This UN-Habitat Global Urban Lecture explains why such a definition is needed.
The country fact sheets in the degree of urbanisation page are used to inform the discussion on the "global harmonized definition of cities and settlements".